In known bi-directional rotary shaft seals the pumping elements whether they be raised ribs, raised triangles, or recessed triangles, lie wholly on the downstream tapered side of the sealing surface whereby to provide wedge shaped spaces for pumping, the tapered side must be deformed to cylindrical form and further expanded to take care of wear. Thus, the contact pressure between the seal and the shaft must be quite high with resulting rapid wear. Moreover, the tooling for molding known seals is quite complex and expensive.